Ivana Zanella

Carbon nanotubes interacting with vitamins: First principles calculations

Electronic and structural properties of carbon nanotubes interacting with vitamins C and B3 radicals are analyzed through the density functional theory. The radical adsorptions result in modifications on the structural and electronic properties of the original carbon nanotubes. The strong adsorptions resulting from the combination of the carbon nanotubes with ascorbic acid and nicotinamide allow the manipulation of the resulting systems in a stable way. These results are extremely relevant in order to identify the potential applications of functionalized carbon nanotubes as drug delivery systems or molecule sensors.

Nicotine adsorption on single wall carbon nanotubes.

This work reports a theoretical study of nicotine molecules interacting with single wall carbon nanotubes (SWCNTs) through ab initio calculations within the framework of density functional theory (DFT). Different adsorption sites for nicotine on the surface of pristine and defective (8,0) SWCNTs were analyzed and the total energy curves, as a function of molecular position relative to the SWCNT surface, were evaluated. The nicotine adsorption process is found to be energetically favorable and the molecule-nanotube interaction is intermediated by the tri-coordinated nitrogen atom from the nicotine. It is also predicted the possibility of a chemical bonding between nicotine and SWCNT through the di-coordinated nitrogen.

Metal-doped carbon nanotubes interacting with vitamin C

In this paper, the structural, electronic and magnetic properties of carbon nanotubes doped with Al, Fe, Mn and Ti atoms interacting with vitamin C molecules are studied through first principles simulations based on the density functional theory. The charge transfers are obtained from the vitamins into the tubes for adsorption and substitutional doping cases. The highest binding energies of vitamin C molecules are calculated for the Al substitutional and Ti adsorbed cases, with values of about 1.20 and 3.26 eV, respectively. The results demonstrated that, depending on doping, the spin polarizations and the conductance characters of the systems can change, which could be relevant to improve the molecule adsorption on carbon nanostructures.

Molecules with Biological Interest Adsorbed on Carbon Nanostructures

In the last decade, carbon nanostructures have been exhaustively studied mainly associated with their application in biosensors and drug delivery systems. In this context, the present chapter introduces several studies combining amino acids and pharmaceutical drugs with carbon nanostructures such as graphene, carbon nanotubes and fullerene. More specifically, the biomolecules under focus are the amino acid cysteine and the pharmaceutical drugs nimesulide, meloxicam and zidovudine. These molecules can be considered models for different chemical interactions or adsorptions with carbon nanostructures. The adsorptions analysed suggest possible applications such as biosensors or drug delivery depending on the use of particular pristine or functionalised carbon nanomaterials.

Carboxylated capped carbon nanotubes interacting with nimesulide molecules: applied electric fields effects

Interactions of carboxylated capped carbon nanotubes with nimesulide molecules under electric fields were investigated by ab initio simulations. Repulsive forces between the nimesulide molecules and the carboxyl group of the carbon nanotubes, except for the nimesulide radical configuration, were observed. To keep the original molecule in the pristine form, electric fields with different intensities were applied, where changes in the behavior of the interactions between the molecules were noticed. It was shown that the intensity of the interaction between the nimesulide and the hydrophilic carboxylated capped carbon nanotube can be modulated by the action of the external electric fields making promising systems for drug delivery applications.